Power distribution bus with protection and alarming

ABSTRACT

Power distribution busses and methods are disclosed that provide flexible protection and alarming capabilities. Various embodiments provide interchangeability of fuses and circuit breakers within the same power distribution bus configuration. These various embodiments also provide discrete alarming for fused lines, discrete alarming for lines with circuit breakers, combined alarming for lines having mixed forms of protection, and/or selectable alarming such as combined versus discrete in relation to employing all fused lines, employing all circuit breaker protected lines, or employing mixed line protection.

TECHNICAL FIELD

The present invention relates to power distribution units and providingpower from a bus within the power distribution unit. More particularly,the present invention relates to providing protection and alarming forthe bus within the power distribution unit.

BACKGROUND

Power distribution units generally provide current to downstream devicesoperating at a given voltage. A bus is included in the powerdistribution unit and acts as a voltage node that provides the currentto the devices. The current that is provided to each individual devicegenerally falls within an acceptable range. However, one or moredownstream devices may draw more current than normal due to a heavierthan normal load or due to a device malfunction. For purposes ofprotecting both the power distribution unit and the downstream device,it is desirable to block current from the power distribution unit to thedownstream device when the current drawn by the device exceeds athreshold amount.

Limiting the current to the downstream device is often done by includinga fuse in each line leading to each device from the bus. The fuse oftenprovides an alarm voltage so that when the fuse blows due to excessivecurrent, the alarm is triggered However, the conventional use of fusesin power distribution busses has drawbacks when multiple lines of powerare being provided by the power distribution unit because the alarmcircuit of conventional power distribution units indicates that a fuseis blown but does not indicate which line is blocked due to a blownfuse. Furthermore, conventional power distribution units that areconfigured to operate with fuses are not configured to operate withcircuit breakers on some or all lines.

Circuit breakers are used by some conventional power distribution unitsto limit the current in each line. However, conventional powerdistribution units using circuit breakers suffer from the same drawbacksas those using fuses. A general alarm is generated by the alarm circuitof a conventional power distribution in response to a tripped breaker,but no indication of the particular line that is blocked is provided.Furthermore, conventional power distribution units that are configuredto operate with a circuit breaker are not configured to also operatewith a fuse on some or all lines.

It may be useful in some instances to have fuses on some of the linesoutput by the power distribution bus while having circuit breakers onother lines. Circuit breakers often have an alarming capability thatfunctions by receiving voltage from a voltage source, such as from thealarm circuit itself. Fuses often have an alarming capability thatfunctions by channeling voltage from the power distribution line to thealarm circuitry. Therefore, conventional power distribution units havenot permitted interchanging fuses with circuit breakers.

Thus, there is a need in the art for more flexible protection andalarming capabilities for power distribution buses.

SUMMARY

The embodiments of the present invention address the problems discussedabove and others by providing a power distribution bus with flexibleprotection and alarming features. Various embodiments permit fuses to bemixed with circuit breakers, permit discrete alarming for each line fromthe bus, permit combined alarming for the lines of the bus, and/orpermit selectable discrete or combined alarming.

The present invention may be viewed as a method of employing fuses andcircuit breakers with a power distribution bus. The method involvesinserting a fuse with an alarm connector in a first location pluggedinto the bus for receiving power from the power distribution bus andinserting a circuit breaker with a pair of alarm connectors in a secondlocation plugged into the bus for receiving power from the powerdistribution unit. The method also involves inhibiting a response froman alarm circuit electrically linked to the first location and secondlocation until the fuse is blown or until the circuit breaker istripped.

The present invention may be viewed as a power distribution bus alarmcircuit. The power distribution bus includes a first and a secondsocket, each having three alarm connections and two power connections.The bus also includes an alarm circuit connected to first and secondalarm connections of the first and second sockets, with the alarmcircuit being responsive to a voltage being applied from the first ofthe three connections of the first or second socket and being responsiveto a voltage being applied across second and third connections of thefirst or second sockets. The bus additionally includes a voltage sourceelectrically connected to third alarm connections of the first andsecond sockets. The bus also includes a fuse positioned in the firstsocket, with the fuse electrically interconnecting the two powerconnections and isolating the first alarm connection from the powerconnection when in a non-blown state. Additionally, the bus includes acircuit breaker positioned in the second socket, with the circuitbreaker electrically interconnecting the two power connections when in anon-tripped state and electrically interconnecting the second and thirdalarm connections when in a tripped state.

The present invention may be viewed as another method of employing fusesand circuit breakers with a power distribution bus. The method involvesinserting a fuse with an alarm connector in a first location in the busfor receiving power from the power distribution unit and inserting acircuit breaker with a pair of alarm connectors in a second location inthe bus for receiving power from the power distribution unit. The methodadditionally involves inhibiting a response from a first alarm circuitelectrically linked to the first location until the fuse is blown andinhibiting a response from a second alarm circuit electrically linked tothe second location until the circuit breaker is tripped.

The present invention may be viewed as another power distribution busalarm circuit. The bus includes a first and a second socket, with eachhaving three alarm connections and two power connections. The busincludes a first alarm circuit connected to first and second alarmconnections of the first socket, with the alarm circuit being responsiveto a voltage being applied from the first of the three connections ofthe first socket and being responsive to a voltage being applied acrosssecond and third connections of the first socket. The bus also includesa second alarm circuit connected to first and second alarm connectionsof the second socket, with the alarm circuit being responsive to avoltage being applied from the first of the three connections of thesecond socket and being responsive to a voltage being applied acrosssecond and third connections of the second socket. The bus additionallyincludes a voltage source electrically connected to third alarmconnections of the first and second sockets. Also, the bus includes afuse positioned in the first socket, with the fuse electricallyinterconnecting the two power connections and isolating the first alarmconnection from the power connection when in a non-blown state.Additionally, the bus includes a circuit breaker positioned in thesecond socket, with the circuit breaker electrically interconnecting thetwo power connections when in a non-tripped state and electricallyinterconnecting the second and third alarm connections when in a trippedstate.

The present invention may be viewed as another method of employing fusesand circuit breakers with a power distribution bus. The method involvesinserting a fuse with an alarm connector in a first location in the busfor receiving power from the power distribution unit and inserting acircuit breaker with a pair of alarm connectors in a second location inthe bus for receiving power from the power distribution unit. The methodalso involves electrically connecting the first location to a firstalarm circuit or a second alarm circuit and electrically connecting thesecond location to the first alarm circuit or to a third alarm circuit.Additionally, the method involves inhibiting a response from the firstalarm circuit or second alarm circuit electrically linked to the firstlocation until the fuse is blown and inhibiting a response from thefirst alarm circuit or third alarm circuit electrically linked to thesecond location until the circuit breaker is tripped.

The present invention may be viewed as another power distribution busalarm circuit. The power distribution bus includes a first and a secondsocket, with each having three alarm connections and two powerconnections. The bus also includes a voltage source electricallyconnected to third alarm connections of the first and second sockets.Additionally, the bus includes a fuse positioned in the first socket,with the fuse electrically interconnecting the two power connections andisolating the first alarm connection from the power connection when in anon-blown state. The bus also includes a circuit breaker positioned inthe second socket, with the circuit breaker electrically interconnectingthe two power connections when in a non-tripped state and electricallyinterconnecting the second and third alarm connections when in a trippedstate. The bus additionally includes a first conductive path extendingfrom the first alarm connection of the first socket, with the firstconductive path including a first diode that prevents current flowbetween the first alarm connection of the first socket and the firstalarm connection of the second socket. The bus also includes a secondconductive path extending from the first alarm connection of the secondsocket, with the second conductive path including a diode that preventscurrent flow between the first alarm connection of the second socket andthe first alarm connection of the first socket. The bus further includesa third conductive path extending from the second alarm connection ofthe first socket, with the third conductive path including a diode thatprevents current flow between the second alarm connection of the firstsocket and the second alarm connection of the second socket. The busalso includes a fourth conductive path extending from the second alarmconnection of the second socket, with the fourth conductive pathincluding a diode that prevents current flow between the second alarmconnection of the second socket and the second alarm connection of thefirst socket.

The present invention may also be viewed as a method of employing fuseswith a power distribution bus. The method involves inserting a firstfuse with an alarm connector in a first location in the bus forreceiving power from the power distribution unit and inserting a secondfuse with an alarm connector in a second location in the bus forreceiving power from the power distribution unit. The method alsoinvolves inhibiting a response from a first alarm circuit electricallylinked to the first location until the first fuse is blown andinhibiting a response from a second alarm circuit electrically linked tothe second location until the second fuse is blown.

The present invention may be viewed as a power distribution bus alarmcircuit. The power distribution bus includes a first and a secondsocket, each having an alarm connection and two power connections. Thebus also includes a first alarm circuit connected to the alarmconnection of the first socket, with the first alarm circuit beingresponsive to a voltage being applied from the alarm connection of thefirst socket. The bus additionally includes a second alarm circuitconnected to the alarm connection of the second socket, with the secondalarm circuit being responsive to a voltage being applied from the alarmconnection of the second socket. Also, the bus includes a first fusepositioned in the first socket, with the first fuse electricallyinterconnecting the two power connections and isolating the alarmconnection of the first socket from the power connection when in anon-blown state. The bus also includes a second fuse positioned in thesecond socket, with the second fuse electrically interconnecting the twopower connections isolating the alarm connection of the second socketwhen in a non-blown state.

The present invention may be viewed as a method of employing circuitbreakers with a power distribution bus. The method involves inserting afirst circuit breaker with a pair of alarm connectors in a firstlocation in the bus for receiving power from the power distribution unitand inserting a second circuit breaker with a pair of alarm connectorsin a second location in the bus for receiving power from the powerdistribution unit. The method further involves inhibiting a responsefrom a first alarm circuit electrically linked to the first locationuntil the first circuit breaker is tripped and inhibiting a responsefrom a second alarm circuit electrically linked to the second locationuntil the second circuit breaker is tripped.

The present invention may be viewed as another power distribution busalarm circuit. The bus includes a first and a second socket, each havingtwo alarm connections and two power connections. The bus also includes afirst alarm circuit connected to first and second alarm connections ofthe first socket, with the alarm circuit being responsive to a voltagebeing applied across the two connections of the first socket. The busadditionally includes a second alarm circuit connected to first andsecond alarm connections of the second socket, with the alarm circuitbeing responsive to a voltage being applied across the two connectionsof the second socket. The bus also includes a voltage sourceelectrically connected to one of the two connections of the first andsecond sockets. The bus includes a first circuit breaker positioned inthe first socket, with the first circuit breaker electricallyinterconnecting the two power connections when in a non-tripped stateand electrically interconnecting the two alarm connections when in anon-blown state. The bus also includes a second circuit breakerpositioned in the second socket, with the second circuit breakerelectrically interconnecting the two power connections when in anon-tripped state and electrically interconnecting the two alarmconnections when in a tripped state.

The present invention may be viewed as another method of employing fuseswith a power distribution bus. The method involves inserting a firstfuse with an alarm connector in a first location in the bus forreceiving power from the power distribution unit and inserting a secondfuse with an alarm connector in a second location in the bus forreceiving power from the power distribution unit. The method furtherinvolves electrically connecting the first location to a first alarmcircuit or a second alarm circuit and electrically connecting the secondlocation to the first alarm circuit or to a third alarm circuit.Additionally, the method involves inhibiting a response from the firstalarm circuit or second alarm circuit electrically linked to the firstlocation until the first fuse is blown and inhibiting a response fromthe first alarm circuit or third alarm circuit electrically linked tothe second location until the second fuse is blown.

The present invention may be viewed as another power distribution busalarm circuit. The bus includes a first and a second socket, with eachhaving an alarm connection and two power connections. The bus alsoincludes a first fuse positioned in the first socket, with the firstfuse electrically interconnecting the two power connections andisolating the alarm connection of the first socket from the powerconnection when in a non-blown state. The bus includes a second fusepositioned in the second socket, with the second fuse electricallyinterconnecting the two power connections and isolating the alarmconnection of the second socket from the power connection when in anon-blown state. The bus includes a first conductive path extending fromthe alarm connection of the first socket and a second conductive pathextending from the alarm connection of the second socket. The bus alsoincludes a third conductive path extending from the alarm connection ofthe first socket and a fourth conductive path extending from the alarmconnection of the second socket.

The present invention may be viewed as another method of employingcircuit breakers with a power distribution bus. The method involvesinserting a first circuit breaker with a pair of alarm connectors in afirst location in the bus for receiving power from the powerdistribution unit and inserting a second circuit breaker with a pair ofalarm connectors in a second location in the bus for receiving powerfrom the power distribution unit. The method also involves electricallyconnecting the first location to a first alarm circuit or a second alarmcircuit and electrically connecting the second location to the firstalarm circuit or to a third alarm circuit. The method additionallyinvolves inhibiting a response from the first alarm circuit or secondalarm circuit electrically linked to the first location until the firstcircuit breaker is tripped. Also, the method involves inhibiting aresponse from the first alarm circuit or third alarm circuitelectrically linked to the second location until the second circuitbreaker is tripped.

The present invention may be viewed as another power distribution busalarm circuit. The bus includes a first and a second socket, with eachhaving two alarm connections and two power connections. The bus alsoincludes a voltage source electrically connected to one of the alarmconnections of the first and second sockets. The bus includes a firstcircuit breaker positioned in the first socket, with the first circuitbreaker electrically interconnecting the two power connections when in anon-tripped state and electrically interconnecting the two alarmconnections when in a tripped state. The bus also includes a secondcircuit breaker positioned in the second socket, with the second circuitbreaker electrically interconnecting the two power connections when in anon-tripped state and electrically interconnecting the alarm connectionswhen in a tripped state. The bus additionally includes a firstconductive path extending from the alarm connection of the first socketnot connected to the voltage source and a second conductive pathextending from the alarm connection of the second socket not connectedto the voltage source.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a protection and alarming configurationemploying discrete alarming with fuses.

FIG. 2 is a schematic of a protection and alarming configurationemploying discrete alarming with circuit breakers.

FIG. 3 is a schematic of a protection and alarming configurationemploying selectable alarming with fuses.

FIG. 4 is a schematic of a protection and alarming configurationemploying selectable alarming with circuit breakers.

FIG. 5 is a schematic of a protection and alarming configurationemploying combined alarming with mixed fuses and circuit breakers.

FIG. 6 is a schematic of a protection and alarming configurationemploying discrete alarming with mixed fuses and circuit breakers.

FIG. 7 is a schematic of a protection and alarming configurationemploying selectable alarming with mixed fuses and circuit breakers.

DETAILED DESCRIPTION

FIG. 1 shows a protection and alarm configuration 100 for a powerdistribution bus 146. This configuration permits fuses to be used forprotection while permitting discrete alarming for each distributionline. Several manufacturers make suitable fuses, such as the CooperBussman TPCDS-BUL disconnect in conjunction with the Cooper Bussman TPCseries fuse. Although two individual distribution lines are shown ineach of the drawings, it is to be understood that only two are shown tosimplify understanding of the protection and alarm configurations andthat any number of distribution lines may be applicable to the variousprotection and alarming configurations.

A voltage is provided on the power distribution bus 146 to a terminal106 of a first socket 102 and to a terminal 110 of a second socket 104.The first socket has a fuse 101 that passes current from the bus 146 toa second terminal 108 that is connected to the downstream device 148.Likewise, the second socket has a fuse 103 that passes current from thebus 146 to a second terminal 112 that is connected to the downstreamdevice 150. The terminals 106, 108, 110, and 112 may be of various typessuch as permanent connections or temporary connections where the alarmconfiguration circuitry 100 is contained in a plug-in module. The fuses101, 103 protect the power distribution unit and downstream devices 148,150 by breaking the current pathway when the current is excessive toeither of the devices 148, 150.

The first socket 102 may have three alarm connections 114, 116, and 118,and the second socket 104 may have three alarm connections 120, 122,124. However, in this embodiment only one alarm connection 116, 122 ofthe each socket 102, 104 is used. The alarm connection 116 connects toan alarm circuit interface 130 through a conductor 126 forming aconductive path from the first socket 102. The interface 130 may be anysuitable connection, permanent or temporary, that establishes continuitybetween the socket 102 and an alarm circuit 134. An alarm circuit 134,as is known in the art, may generate a remote alarm signal 138, such asby triggering an internal relay (not shown), and/or may light a lightemitting diode (LED) 140 to provide a visual indication as to thecondition of the fuse 101.

The alarm connection 122 connects to an alarm circuit interface 132through a conductor 128 forming a conductive path from the second socket104. The interface 132 may be of the same type as interface 130. Theinterface 132 provides continuity between the second socket 104 and asecond alarm circuit 136. The second alarm circuit 136 may be of thesame type as the alarm circuit 134 to generate a remote alarm signal 142and/or light the LED 144.

The fuse 101 of the first socket 102 isolates the distribution bus 146from the alarm connection 116 when the fuse 101 is not blown, but whenthe fuse 101 blows the distribution bus 146 is channeled to the alarmconnection 116 through the fuse 101. Likewise, the fuse 103 of thesecond socket isolates the distribution bus 146 from the alarmconnection 122 when the fuse 103 is not blown. The first alarm circuit134 does not respond to fuse 103 blowing, and the second alarm circuit136 does not respond to the fuse 101 blowing. Therefore, discretealarming for each line feeding power to devices 148, 150 is provided topermit individual monitoring.

FIG. 2 shows a protection and alarm configuration 200 for a powerdistribution bus (not shown). This configuration permits circuitbreakers to be used for protection while permitting discrete alarmingfor each distribution line. Examples of suitable circuit breakersinclude the Carling CA1-X0-07-819-AXX-C series, the Eaton AM1R-B2-AC23D-AS2, and the Airpax LMLK-1-RLS4-31462-10V. As previouslydiscussed, two individual distribution lines are shown to simplifyunderstanding of the protection and alarm configurations and any numberof distribution lines may be applicable.

The alarm configuration 200 includes a first socket 202 having aterminal 206 that connects to a bus and a terminal 208 that leads to adownstream device. A circuit breaker 201 is inserted into the firstsocket 202. The circuit breaker 201 passes current from terminal 206 toterminal 208 until the current becomes excessive. Once the current isexcessive, the circuit breaker 201 trips to stop current flow betweenthe terminals 206, 208. The alarm configuration 200 also includes asecond socket 204 having a terminal 210 that connects to a bus and aterminal 212 that leads to another downstream device. A circuit breaker203 is inserted into the second socket 204. The circuit breaker 203passes current from terminal 210 to terminal 212 until the currentbecomes excessive. Once the current is excessive, the circuit breaker203 trips to stop current flow between the terminals 210, 212.

As discussed above with reference to FIG. 1, the sockets 202, 204 mayinclude three alarm connections including connection 214, 216, and 218for socket 202 and connections 220, 222, and 224 for socket 204.However, the configuration 200 only uses connections 214 and 218 forsocket 202 and connections 220 and 224 for socket 204 to generate analarm because connections 216 and 222, although connected to the circuitbreakers 201, 203 when in a non-tripped state, are not connected to thealarm circuits 234, 236. The alarm connections 218, 224 are connected toa voltage source 246 through a conductor 250 and an interface 248. Thevoltage source shown provides negative voltage to the alarm circuits butone skilled in the art will recognize that positive voltage could beprovided instead.

Tripping the circuit breaker 201 causes the alarm connection 218 to beconnected to the alarm connection 214 and current flows between thevoltage source 248 and the alarm circuit 234 through conductor 226 andinterface 230. Likewise, tripping the circuit breaker 203 causes thealarm connection 224 to be connected to the alarm connection 220 andcurrent flows between the voltage source 248 and the alarm circuit 236through conductor 228 and interface 232. Thus, when circuit breaker 201trips, alarm circuit 234 generates a remote alarm signal 238 and/orlights LED 240. When circuit breaker 203 trips, alarm circuit 236generates a remote alarm signal 242 and/or lights LED 244. Circuitbreaker 201 has no effect on alarm circuit 236 and circuit breaker 203has no effect on alarm circuit 234. Therefore, discrete alarming isprovided for each line to permit individual monitoring.

FIG. 3 shows a protection and alarm configuration 300 for a powerdistribution bus (not shown). This configuration permits fuses to beused for protection while permitting selection of discrete alarming foreach distribution line or a single alarm responsive to several of thedistribution lines. As previously discussed, two individual distributionlines are shown to simplify understanding of the protection and alarmconfigurations and any number of distribution lines may be applicable.

The alarm configuration 300 includes a first socket 302 with a fuse 301and a second socket 304 with a fuse 303. The fuse 301 carries currentbetween terminal 306 and terminal 308, and fuse 303 carries currentbetween terminal 310 and 312. Socket 302 may have three alarmconnections 314, 316, and 318 and socket 304 may have three alarmconnections 320, 322, and 324. However, only alarm connections 316 and322 are used.

If a single alarm responsive to all lines is to be used, then alarmcircuit 333 is connected to interface 331. When fuse 301 blows, currentis channeled between the bus terminal 306 and alarm circuit 333 throughalarm connection 316. Alarm connection 316 is connected to the interface331 through a conductive path 326. Conductive path 326 may include adiode 346 which is discussed in more detail below with reference todiscrete alarming for configuration 300. The bus voltage at terminal 306is assumed to be negative for this diode direction. When alarm circuit333 receives power from socket 302, a remote alarm signal 335 isgenerated and/or the LED 337 lights.

Additionally, if a single alarm responsive to all lines is to be used,then when fuse 303 blows, current is channeled between the bus terminal310 and alarm circuit 333 through alarm connection 322. Alarm connection322 is connected to the interface 331 through a conductive path 328.Conductive path 328 may include a diode 348 which is also discussed inmore detail below with reference to discrete alarming for configuration300. As mentioned, negative voltage is assumed at bus terminal 306 forthis diode direction. When alarm circuit 333 receives power from socket302, the remote alarm signal 335 is generated and/or LED 337 lights asis the case when fuse 301 blows.

If discrete alarming is desired, then alarm circuit 336 is connected tointerface 330 and alarm circuit 334 is connected to interface 332 ratherthan alarm circuit 333 being connected to interface 331. If both singleand discrete alarming are desired, alarm circuit 333 can be connected tointerface 331 as well. If discrete alarming is implemented, then whenfuse 301 blows, current flows between bus terminal 306 and alarm circuit336. No current flows to alarm circuit 334 due to the fuse 301 beingblown because diode 348 prevents current from flowing in that directionthrough conductive path 328. Alarm circuit 336 generates a remote alarmsignal 342 and/or lights LED 344 in response to fuse 301 blowing.

Additionally, if discrete alarming is implemented, then when fuse 303blows, current flows between bus terminal 310 and alarm circuit 334. Nocurrent flows to alarm circuit 336 because diode 346 prevents currentfrom flowing in that direction through conductive path 326. Alarmcircuit 334 generates a remote alarm signal 338 and/or lights LED 340 inresponse to fuse 303 blowing.

FIG. 4 shows a protection and alarm configuration 400 for a powerdistribution bus (not shown). This configuration permits circuitbreakers to be used for protection while permitting selection ofdiscrete alarming for each distribution line or a single alarmresponsive to several of the distribution lines. As previouslydiscussed, two individual distribution lines are shown to simplifyunderstanding of the protection and alarm configurations and any numberof distribution lines may be applicable.

The configuration 400 has a first socket 402 and second socket 404. Acircuit breaker 401 located in the first socket 402 channels currentbetween the bus terminal 406 and terminal 408 that leads to thedownstream device. A circuit breaker 403 located in the second socket404 channels current between the bus terminal 410 and the terminal 412that leads to another downstream device. Both sockets may have threealarms connections such as connections 414, 416, and 418 of socket 402and connections 420, 422, and 424 of socket 404. However, configuration400 uses only connections 414, 418, 420, and 424 to provide current tothe alarm circuits.

If a single alarm is to be used for several lines, then alarm circuit433 is connected to interface 430. When circuit breaker 401 trips, alarmconnection 414 is connected to alarm connection 418 and current isestablished between the voltage source 446 and the alarm circuit 433.The voltage source 446, which provides negative voltage as shown in FIG.4 or alternatively positive voltage, passes current through conductivepath 450 and socket 402 and also through conductive path 425 whenproviding power to alarm circuit 433. A diode 449 is included in path425 and is discussed in more detail below with reference toconfiguration 400 being implemented with discrete alarming. The alarmcircuit 433 generates a remote alarm signal 435 and/or lights LED 437 inresponse to fuse 401 blowing.

If the single alarm is in use, then when circuit breaker 403 trips,alarm connection 420 is connected to alarm connection 424 and current isestablished between the voltage source 446 and the alarm circuit 433.The voltage source 446 passes current through conductive path 450 andsocket 404 and also through conductive path 427 when providing power toalarm circuit 433. A diode 451 is included in path 427 and is discussedin more detail below with reference to configuration 400 beingimplemented with discrete alarming. The alarm circuit 433 generates aremote alarm signal 435 and/or lights LED 437 in response to fuse 403blowing.

If discrete alarming is to be used for each line, then alarm circuit 434is connected to interface 431 and alarm circuit 436 is connected tointerface 432 instead of alarm circuit 433 being connected to interface430. If both discrete alarming and a single alarm are desired, thenalarm circuit 433 may also be connected to interface 430. If discretealarming is implemented, then when fuse 401 blows, current isestablished between the voltage source 446 and the alarm circuit 434.Current is provided by the voltage source 446 through conductive path450 and conductive path 426. Diode 451 prevents power from being appliedto alarm circuit 436 in response to fuse 401 blowing. Alarm circuit 434generates a remote alarm signal 438 and/or lights LED 440 in response tofuse 401 blowing.

If discrete alarming is implemented, then when fuse 403 blows, currentis established between the voltage source 446 and the alarm circuit 436.Current is provided by the voltage source 446 through conductive path450 and conductive path 428. Diode 449 prevents power from being appliedto alarm circuit 434 in response to fuse 403 blowing. Alarm circuit 436generates a remote alarm signal 442 and/or lights LED 444 in response tofuse 403 blowing.

FIG. 5 shows a protection and alarm configuration 500 for a powerdistribution bus (not shown). This configuration permits fuses andcircuit breakers to be mixed for protection while a single alarm isresponsive to several of the distribution lines. At any given time, onesocket may have a fuse and the other may have a circuit breaker, bothmay have fuses, or both may have circuit breakers. As previouslydiscussed, two individual distribution lines are shown to simplifyunderstanding of the protection and alarm configurations and any numberof distribution lines may be applicable.

The configuration 500 includes a socket 502 and a socket 504. Currentfrom the power distribution bus (not shown) is provided through a fuseor circuit breaker in socket 502 from the bus terminal 506 to theterminal 508 that leads to a downstream device. Current from the powerdistribution bus is also provided through a fuse or circuit breaker insocket 504 from the bus terminal 510 to the terminal 512.

When a circuit breaker is used in the first socket 502, once the circuitbreaker trips, current is established between a voltage source 546 andan alarm circuit 534 through connections 514 and 518 of socket 502.Current passes through interface 540 connected to voltage source 546,through conductive paths 548 and 526, and through interface 530.Conductive path 526 may include a diode 550 that prevents a trippedcircuit breaker in socket 504 from providing voltage from supply 546 tothe fuse alarm interface 532 through the first socket 502 when the firstsocket 502 contains a non-tripped circuit breaker. Diode 550 is usefulwhere the bus voltage normally supplied to interface 532 due to a blownfuse is a different voltage than the supply voltage 546. Alarm circuit534 generates a remote alarm signal 536 and/or lights LED 538 inresponse to a tripped circuit breaker in socket 502.

When a circuit breaker is used in the second socket 504, once thecircuit breaker trips, current is established between the voltage source546 and the alarm circuit 534 through connections 520 and 524 of socket504. Current passes through interface 540 connected to voltage source546, through conductive paths 548 and 527, and through interface 530.Conductive path 527 may include a diode 552 that prevents a trippedcircuit breaker in socket 502 from providing voltage from supply 546 tothe fuse alarm interface 532 through the second socket 504 when thesecond socket contains a non-tripped circuit breaker. Alarm circuit 534generates the remote alarm signal 536 and/or lights LED 538 in responseto a tripped circuit breaker in the second socket 504.

When a fuse is used in the first socket 502, once the fuse has blown,current is established between the bus and the alarm circuit 534 throughconnection 516. Current passes through interface 532 and throughconductive path 528. Conductive path 528 may include a diode 554 thatprevents a blown fuse in socket 504 from providing voltage from the busto the circuit breaker alarm interface 530 through conductive paths 528and 526 when socket 502 has a non-tripped circuit breaker. Alarm circuit534 generates a remote alarm signal 536 and/or lights LED 538 inresponse to a blown fuse in socket 502.

When a fuse is used in the second socket 504, once the fuse has blown,current is established between the bus and the alarm circuit 534 throughconnection 522. Current passes through interface 532 and throughconductive path 529. Conductive path 529 may include a diode 556 thatprevents a blown fuse in socket 502 from providing voltage from the busto the circuit breaker alarm interface 530 through conductive paths 529and 527 when socket 504 has a non-tripped circuit breaker. Alarm circuit534 generates the remote alarm signal 536 and/or lights LED 538 inresponse to a blown fuse in socket 504.

FIG. 6 shows a protection and alarm configuration 600 for a powerdistribution bus (not shown). This configuration permits fuses andcircuit breakers to be mixed for protection while discrete alarming isprovided for each distribution line. At any given time, one socket mayhave a fuse and the other may have a circuit breaker, both may havefuses, or both may have circuit breakers. As previously discussed, twoindividual distribution lines are shown to simplify understanding of theprotection and alarm configurations and any number of distribution linesmay be applicable.

The configuration 600 includes a socket 602 and a socket 604. Currentfrom the power distribution bus (not shown) is provided through a fuseor circuit breaker in socket 602 from the bus terminal 606 to theterminal 608 that leads to a downstream device. Current from the powerdistribution bus is also provided through a fuse or circuit breaker insocket 604 from the bus terminal 610 to the terminal 612.

When a fuse is used in the first socket 602, once the fuse has blown,current is established between the bus and alarm circuit 634. Currentflows through alarm connection 616, through conductive path 646, andthrough interface 631. Alarm circuit 634 generates a remote alarm signal638 and/or lights LED 640 in response to a blown fuse in socket 602.

When a fuse is used in the second socket 604, once the fuse has blown,current is established between the bus and alarm circuit 636. Currentflows through alarm connection 622, through conductive path 648, andthrough interface 650. Alarm circuit 636 generates a remote alarm signal642 and/or lights LED 644 in response to a blown fuse in socket 604.

When a circuit breaker is used in the first socket 602, once the circuitbreaker trips, current is established between the voltage source 666 andthe alarm circuit 634. Voltage source 666 can provide a positive ornegative voltage. Current flows through interface 668, throughconductive path 628, through alarm connections 614 and 618, throughconductive path 626, and through interface 630. Alarm circuit 634generates the remote alarm signal 638 and/or lights LED 640 in responseto a tripped circuit breaker in socket 602.

When a circuit breaker is used in the second socket 604, once thecircuit breaker trips, current is established between the voltage source666 and the alarm circuit 636. Current flows through interface 668,through conductive path 629, through alarm connections 624 and 620,through conductive path 627, and through interface 632. Alarm circuit636 generates the remote alarm signal 642 and/or lights LED 644 inresponse to a tripped circuit breaker in socket 604.

FIG. 7 shows a protection and alarm configuration 700 for a powerdistribution bus (not shown). This configuration permits fuses andcircuit breakers to be mixed for protection while permitting selectionof discrete alarming for each distribution line or a single alarmresponsive to several of the distribution lines. At any given time, onesocket may have a fuse and the other may have a circuit breaker, bothmay have fuses, or both may have circuit breakers. As previouslydiscussed, two individual distribution lines are shown to simplifyunderstanding of the protection and alarm configurations and any numberof distribution lines may be applicable.

The configuration 700 includes a socket 702 and a socket 704. Currentfrom the power distribution bus (not shown) is provided through a fuseor circuit breaker in socket 702 from the bus terminal 706 to theterminal 708 that leads to a downstream device. Current from the powerdistribution bus is also provided through a fuse or circuit breaker insocket 704 from the bus terminal 710 to the terminal 712.

When discrete alarms are used for each line and a fuse is placed insocket 702, once the fuse blows, current is established between the busand alarm circuit 744. Current flows through alarm connection 716,through conductive path 764, and through interface 770. The alarmcircuit 744 generates a remote alarm signal 748 and/or lights LED 750 inresponse to a blown fuse in socket 702.

When discrete alarms are used for each line and a fuse is placed insocket 704, once the fuse blows, current is established between the busand alarm circuit 746. Current flows through the alarm connection 722,through conductive path 766, and through interface 768. Alarm circuit746 generates a remote alarm signal 752 and/or lights LED 754 inresponse to a blown fuse in socket 704.

When discrete alarms for each line are used and a circuit breaker isplaced in socket 702, once the circuit breaker trips, current isestablished between voltage source 788 and alarm circuit 744. Currentflows through interface 790, through conductive path 791, through alarmconnections 718 and 714, through conductive path 726, and throughinterface 740. Alarm circuit 744 generates the remote alarm signal 748and/or lights LED 750 in response to a tripped circuit breaker in socket702.

When discrete alarms for each line are used and a circuit breaker isplaced in socket 704, once the circuit breaker trips, current isestablished between the voltage source 788 and alarm circuit 746.Current flows through interface 790, through conductive path 793,through alarm connections 724 and 720, through conductive path 728, andthrough interface 742. Alarm circuit 746 generates the remote alarmsignal 752 and/or lights LED 754 in response to a tripped circuitbreaker in socket 704.

When a single alarm is used for several lines and a fuse is placed insocket 702, once the fuse blows, current is established between the busand the alarm circuit 734. Current flows through alarm connection 716,through conductive path 760, and through interface 732. A diode 784 isplaced in conductive path 760 to prevent current from flowing throughconductive path 762 to conductive path 726 and alarm circuit 744 whendiscrete alarming is used and when a non-tripped circuit breaker is insocket 702 and a blown fuse is in socket 704. Alarm circuit 734generates a remote alarm signal 736 and/or lights LED 738 in response toa blown fuse in socket 702.

When a single alarm is used for several lines and a fuse is placed insocket 704, once the fuse blows, current is established between the busand the alarm circuit 734. Current flows through alarm connection 722,through conductive path 762, and through interface 732. A diode 786 isplaced in conductive path 762 to prevent current from flowing throughconductive path 760 to conductive path 762 and alarm circuit 746 whendiscrete alarming is used and when a non-tripped circuit breaker is insocket 704 and a blown fuse in socket 702. Alarm circuit 734 generatesthe remote alarm signal 736 and/or lights LED 738 in response to a blownfuse in socket 704.

When a single alarm is used for several lines and a circuit breaker isplaced in socket 702, once the circuit breaker trips, current isestablished between voltage source 788 and alarm circuit 734. Currentflows through interface 790, through conductive path 791, through alarmconnections 718 and 714, through conductive path 727, and throughinterface 730. A diode 756 is placed in conductive path 727 to preventcurrent from flowing between the voltage source 788 and the alarmcircuit 744 when discrete alarming is used with a tripped circuitbreaker in socket 704 and a non-tripped circuit breaker in socket 702.Alarm circuit 734 generates the remote alarm signal 736 and/or lightsLED 738 in response to a tripped circuit breaker in socket 702.

When a single alarm is used for several line and a circuit breaker isplaced in socket 704, once the circuit breaker trips, current isestablished between voltage source 788 and alarm circuit 734. Currentflows through interface 790, through conductive path 793, through alarmconnections 724 and 720, through conductive path 729, and throughinterface 730. A diode 758 is placed in conductive path 729 to preventcurrent from flowing between the voltage source 788 and the alarmcircuit 746 when discrete alarming is used with a tripped circuitbreaker in socket 702 and a non-tripped circuit breaker in socket 704.Alarm circuit 734 generates the remote alarm signal 736 and/or lightsLED 738 in response to a tripped circuit breaker in socket 704.

While the invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that various other changes in the form anddetails may be made therein without departing from the spirit and scopeof the invention.

1. A method of employing fuses and circuit breakers with a powerdistribution bus, comprising the steps of: inserting a fuse with analarm connector in a first location plugged into the bus for receivingpower from the power distribution bus; inserting a circuit breaker witha pair of alarm connectors in a second location plugged into the bus forreceiving power from the power distribution bus; inhibiting a responsefrom an alarm circuit electrically linked to the first location andsecond location until the fuse is blown or until the circuit breaker istripped.
 2. The method of claim 1, further comprising the step of:tripping the circuit breaker to deliver power to the alarm circuitthrough the pair of alarm connectors.
 3. The method of claim 1, furthercomprising the step of: blowing the fuse to deliver power to the alarmcircuit through the alarm connector.
 4. The method of claim 1, furthercomprising the steps of: removing the circuit breaker from the secondlocation; inserting a second fuse in the second location; and inhibitinga response from the alarm circuit until either the fuse in the firstlocation or the second fuse is blown.
 5. The method of claim 1, furthercomprising the steps of: removing the fuse from the first location;inserting a second circuit breaker in the first location; and inhibitinga response from the alarm circuit until the first or second circuitbreaker is tripped.
 6. A power distribution bus alarm circuit,comprising: a first and a second socket, each having three alarmconnections and two power connections plugged into the bus; an alarmcircuit connected to first and second alarm connections of the first andsecond sockets, the alarm circuit being responsive to a voltage beingapplied from the first of the three connections of the first or secondsocket and being responsive to a voltage being applied across second andthird connections of the first or second sockets; a voltage sourceelectrically connected to third alarm connections of the first andsecond sockets; a fuse positioned in the first socket, the fuseelectrically interconnecting the two power connections and isolating thefirst alarm connection from the power connection when in a non-blownstate; a circuit breaker positioned in the second socket, the circuitbreaker electrically interconnecting the two power connections when in anon-tripped state and electrically interconnecting the second and thirdalarm connections when in a tripped state.
 7. The power distribution busalarm circuit of claim 6, further comprising: a first conductive pathleading from the first alarm connection of the first socket to the alarmcircuit, the first conductive path including a diode that permitscurrent flow between the first alarm connection of the first socket andthe alarm circuit but prevents current flow between the first alarmconnection of the first socket and the first alarm connection of thesecond socket; a second conductive path leading from the first alarmconnection of the second socket to the alarm circuit, the secondconductive path including a diode that permits current flow between thefirst alarm connection of the second socket and the alarm circuit butprevents current flow between the first alarm connection of the secondsocket and the first alarm connection of the first socket.
 8. The powerdistribution bus alarm circuit of claim 7, further comprising: a thirdconductive path leading from the second alarm connection of the firstsocket to the alarm circuit, the third conductive path including a diodethat permits current flow between the second alarm connection of thefirst socket and the alarm circuit but prevents current flow between thesecond alarm connection of the first socket and the second alarmconnection of the second socket; and a fourth conductive path leadingfrom the second alarm connection of the second socket to the alarmcircuit, the fourth conductive path including a diode that permitscurrent flow between the second alarm connection of the second socketand the alarm circuit but prevents current flow between the second alarmconnection of the second socket and the second alarm connection of thefirst socket.
 9. A method of employing fuses and circuit breakers with apower distribution bus, comprising the steps of: inserting a fuse withan alarm connector in a first location connected to the bus forreceiving power from the power distribution bus; inserting a circuitbreaker with a pair of alarm connectors in a second location connectedto the bus for receiving power from the power distribution bus;inhibiting a response from a first alarm circuit electrically linked tothe first location until the fuse is blown; and inhibiting a responsefrom a second alarm circuit electrically linked to the second locationuntil the circuit breaker is tripped.
 10. The method of claim 9, furthercomprising the step of: tripping the circuit breaker to deliver power tothe second alarm circuit through the pair of alarm connectors.
 11. Themethod of claim 9, further comprising the step of: blowing the fuse todeliver power to the first alarm circuit through the alarm connector.12. The method of claim 9, further comprising the steps of: removing thecircuit breaker from the second location; inserting a second fuse in thesecond location; and inhibiting a response from the second alarm circuituntil the second fuse is blown.
 13. The method of claim 9, furthercomprising the steps of: removing the fuse from the first location;inserting a second circuit breaker in the first location; and inhibitinga response from the first alarm circuit until the second circuit breakeris tripped.
 14. A power distribution bus alarm circuit, comprising: afirst and a second socket, each having three alarm connections and twopower connections; a first alarm circuit connected to first and secondalarm connections of the first socket, the alarm circuit beingresponsive to a voltage being applied from the first of the threeconnections of the first socket and being responsive to a voltage beingapplied across second and third connections of the first socket; asecond alarm circuit connected to first and second alarm connections ofthe second socket, the alarm circuit being responsive to a voltage beingapplied from the first of the three connections of the second socket andbeing responsive to a voltage being applied across second and thirdconnections of the second socket; a voltage source electricallyconnected to third alarm connections of the first and second sockets; afuse positioned in the first socket, the fuse electricallyinterconnecting the two power connections and isolating the first alarmconnection from the power connection when in a non-blown state; acircuit breaker positioned in the second socket, the circuit breakerelectrically interconnecting the two power connections when in anon-tripped state and electrically interconnecting the second and thirdalarm connections when in a tripped state.
 15. The power distributionbus alarm circuit of claim 14, further comprising: a first conductivepath leading from the first alarm connection of the first socket to thefirst alarm circuit; a second conductive path leading from the firstalarm connection of the second socket to the second alarm circuit; athird conductive path leading from the second alarm connection of thefirst socket to the first alarm circuit; and a fourth conductive pathleading from the second alarm connection of the second socket to thesecond alarm circuit.
 16. A method of employing fuses and circuitbreakers with a power distribution bus, comprising the steps of:inserting a fuse with an alarm connector in a first location in the busfor receiving power from the power distribution bus; inserting a circuitbreaker with a pair of alarm connectors in a second location in the busfor receiving power from the power distribution bus; electricallyconnecting the first location to a first alarm circuit or a second alarmcircuit; electrically connecting the second location to the first alarmcircuit or to a third alarm circuit; inhibiting a response from thefirst alarm circuit or second alarm circuit electrically linked to thefirst location until the fuse is blown; and inhibiting a response fromthe first alarm circuit or third alarm circuit electrically linked tothe second location until the circuit breaker is tripped.
 17. The methodof claim 16, further comprising the step of: tripping the circuitbreaker to deliver power to the first or third alarm circuit through thepair of alarm connectors.
 18. The method of claim 16, further comprisingthe step of: blowing the fuse to deliver power to the first or secondalarm circuit through the alarm connector.
 19. The method of claim 16,further comprising the steps of: removing the circuit breaker from thesecond location; inserting a second fuse in the second location; andinhibiting a response from the first or third alarm circuit until thesecond fuse is blown.
 20. The method of claim 16, further comprising thesteps of: removing the fuse from the first location; inserting a secondcircuit breaker in the first location; and inhibiting a response fromthe first or second alarm circuit until the second circuit breaker istripped.
 21. A power distribution bus alarm circuit, comprising: a firstand a second socket, each having three alarm connections and two powerconnections; a voltage source electrically connected to third alarmconnections of the first and second sockets; a fuse positioned in thefirst socket, the fuse electrically interconnecting the two powerconnections and isolating the first alarm connection from the powerconnection when in a non-blown state; a circuit breaker positioned inthe second socket, the circuit breaker electrically interconnecting thetwo power connections when in a non-tripped state and electricallyinterconnecting the second and third alarm connections when in a trippedstate; a first conductive path extending from the first alarm connectionof the first socket, the first conductive path including a first diodethat prevents current flow between the first alarm connection of thefirst socket and the first alarm connection of the second socket; asecond conductive path extending from the first alarm connection of thesecond socket, the second conductive path including a diode thatprevents current flow between the first alarm connection of the secondsocket and the first alarm connection of the first socket; a thirdconductive path extending from the second alarm connection of the firstsocket, the third conductive path including a diode that preventscurrent flow between the second alarm connection of the first socket andthe second alarm connection of the second socket; and a fourthconductive path extending from the second alarm connection of the secondsocket, the fourth conductive path including a diode that preventscurrent flow between the second alarm connection of the second socketand the second alarm connection of the first socket.
 22. The powerdistribution bus alarm circuit of claim 21, further comprising an alarmcircuit linked to first and second alarm connections of the first andsecond sockets, the alarm circuit being responsive to a voltage beingapplied from the first alarm connection of the first or second socketand being responsive to a voltage being applied across second and thirdconnections of the first or second sockets.
 23. The power distributionbus alarm circuit of claim 21, further comprising: a first alarm circuitlinked to the first and second connections of the first socket throughthe first and third conductive paths, the first alarm circuit beingresponsive to a voltage being applied from the first alarm connection ofthe first socket and being responsive to a voltage being applied acrossthe second and third connection of the first socket; and a second alarmcircuit linked to the first and second connections of the second socketthrough the second and fourth conductive paths, the second alarm circuitbeing responsive to a voltage being applied from the first alarmconnection of the second socket and being responsive to a voltage beingapplied across the second and third connection of the second socket. 24.A method of employing fuses with a power distribution bus, comprisingthe steps of; inserting a first fuse with an alarm connector in a firstlocation in the bus for receiving power from the power distribution bus;inserting a second fuse with an alarm connector in a second location inthe bus for receiving power from the power distribution bus; inhibitinga response from a first alarm circuit electrically linked to the firstlocation until the first fuse is blown; and inhibiting a response from asecond alarm circuit electrically linked to the second location untilthe second fuse is blown.
 25. The method of claim 24, further comprisingthe step of: blowing the second fuse to deliver power to the secondalarm circuit through the alarm connector of the second fuse.
 26. Themethod of claim 24, further comprising the step of: blowing the firstfuse to deliver power to the first alarm circuit through the alarmconnector of the first fuse.
 27. A power distribution bus alarm circuit,comprising: a first and a second socket, each having an alarm connectionand two power connections; a first alarm circuit connected to the alarmconnection of the first socket, the first alarm circuit being responsiveto a voltage being applied from the alarm connection of the firstsocket; a second alarm circuit connected to the alarm connection of thesecond socket, the second alarm circuit being responsive to a voltagebeing applied from the alarm connection of the second socket; a firstfuse positioned in the first socket, the first fuse electricallyinterconnecting the two power connections and isolating the alarmconnection of the first socket from the power connection when in anon-blown state; a second fuse positioned in the second socket, thesecond fuse electrically interconnecting the two power connectionsisolating the alarm connection of the second socket when in a non-blownstate.
 28. The power distribution bus alarm circuit of claim 27, furthercomprising: a first conductive path leading from the alarm connection ofthe first socket to the first alarm circuit; and a second conductivepath leading from the alarm connection of the second socket to thesecond alarm circuit.
 29. A method of employing circuit breakers with apower distribution bus, comprising the steps of: inserting a firstcircuit breaker with a pair of alarm connectors in a first location inthe bus for receiving power from the power distribution bus; inserting asecond circuit breaker with a pair of alarm connectors in a secondlocation in the bus for receiving power from the power distribution bus;inhibiting a response from a first alarm circuit electrically linked tothe first location until the first circuit breaker is tripped; andinhibiting a response from a second alarm circuit electrically linked tothe second location until the second circuit breaker is tripped.
 30. Themethod of claim 29, further comprising the step of: tripping the secondcircuit breaker to deliver power to the second alarm circuit through thepair of alarm connectors of the second circuit breaker.
 31. The methodof claim 29, further comprising the step of: tripping the first circuitbreaker to deliver power to the first alarm circuit through the pair ofalarm connectors of the first circuit breaker.
 32. A power distributionbus alarm circuit, comprising: a first and a second socket, each havingtwo alarm connections and two power connections; a first alarm circuitconnected to first and second alarm connections of the first socket, thealarm circuit being responsive to a voltage being applied across the twoconnections of the first socket; a second alarm circuit connected tofirst and second alarm connections of the second socket, the alarmcircuit being responsive to a voltage being applied across the twoconnections of the second socket; a voltage source electricallyconnected to one of the two connections of the first and second sockets;a first circuit breaker positioned in the first socket, the firstcircuit breaker electrically interconnecting the two power connectionswhen in a non-tripped state and electrically interconnecting the twoalarm connections when in a non-blown state; a second circuit breakerpositioned in the second socket, the second circuit breaker electricallyinterconnecting the two power connections when in a non-tripped stateand electrically interconnecting the two alarm connections when in atripped state.
 33. The power distribution bus alarm circuit of claim 32,further comprising: a first conductive path leading from the alarmconnection of the first circuit breaker that is not connected to thevoltage source to the first alarm circuit; and a second conductive pathleading from the alarm connection of the second circuit breaker that isnot connected to the voltage source to the second alarm circuit.
 34. Amethod of employing fuses with a power distribution bus, comprising thesteps of: inserting a first fuse with an alarm connector in a firstlocation in the bus for receiving power from the power distribution bus;inserting a second fuse with an alarm connector in a second location inthe bus for receiving power from the power distribution bus;electrically connecting the first location to a first alarm circuit or asecond alarm circuit; electrically connecting the second location to thefirst alarm circuit or to a third alarm circuit; inhibiting a responsefrom the first alarm circuit or second alarm circuit electrically linkedto the first location until the first fuse is blown; and inhibiting aresponse from the first alarm circuit or third alarm circuitelectrically linked to the second location until the second fuse isblown.
 35. The method of claim 34, further comprising the step of:blowing the second fuse to deliver power to the first or third alarmcircuit through the alarm connector of the second fuse.
 36. The methodof claim 34, further comprising the step of: blowing the first fuse todeliver power to the first or second alarm circuit through the alarmconnector of the first fuse.
 37. A power distribution bus alarm circuit,comprising: a first and a second socket, each having an alarm connectionand two power connections; a first fuse positioned in the first socket,the first fuse electrically interconnecting the two power connectionsand isolating the alarm connection of the first socket from the powerconnection when in a non-blown state; a second fuse positioned in thesecond socket, the second fuse electrically interconnecting the twopower connections and isolating the alarm connection of the secondsocket from the power connection when in a non-blown state; a firstconductive path extending from the alarm connection of the first socket;a second conductive path extending from the alarm connection of thesecond socket; a third conductive path extending from the alarmconnection of the first socket; and a fourth conductive path extendingfrom the alarm connection of the second socket.
 38. The powerdistribution bus alarm circuit of claim 37, further comprising an alarmcircuit linked to the alarm connections of the first and second socketsthrough the first and second conductive paths, the alarm circuit beingresponsive to a voltage being applied from the alarm connection of thefirst or second socket.
 39. The power distribution bus alarm circuit ofclaim 37, further comprising: a first alarm circuit linked to the alarmconnection of the first socket through the third conductive path, thefirst alarm circuit being responsive to a voltage being applied from thefirst alarm connection of the first socket; and a second alarm circuitlinked to the alarm connection of the second socket through the fourthconductive path, the second alarm circuit being responsive to a voltagebeing applied from the alarm connection of the second socket.
 40. Amethod of employing circuit breakers with a power distribution bus,comprising the steps of: inserting a first circuit breaker with a pairof alarm connectors in a first location in the bus for receiving powerfrom the power distribution bus; inserting a second circuit breaker witha pair of alarm connectors in a second location in the bus for receivingpower from the power distribution bus; electrically connecting the firstlocation to a first alarm circuit or a second alarm circuit;electrically connecting the second location to the first alarm circuitor to a third alarm circuit; inhibiting a response from the first alarmcircuit or second alarm circuit electrically linked to the firstlocation until the first circuit breaker is tripped; and inhibiting aresponse from the first alarm circuit or third alarm circuitelectrically linked to the second location until the second circuitbreaker is tripped.
 41. The method of claim 40, further comprising thestep of: tripping the second circuit breaker to deliver power to thefirst or third alarm circuit through the pair of alarm connectors. 42.The method of claim 40, further comprising the step of: tripping thesecond circuit breaker to deliver power to the first or second alarmcircuit through the pair of alarm connectors.
 43. A power distributionbus alarm circuit, comprising: a first and a second socket, each havingtwo alarm connections and two power connections; a voltage sourceelectrically connected to one of the alarm connections of the first andsecond sockets; a first circuit breaker positioned in the first socket,the first circuit breaker electrically interconnecting the two powerconnections when in a non-tripped state and electrically interconnectingthe two alarm connections when in a tripped state; a second circuitbreaker positioned in the second socket, the second circuit breakerelectrically interconnecting the two power connections when in anon-tripped state and electrically interconnecting the alarm connectionswhen in a tripped state; a first conductive path extending from thealarm connection of the first socket not connected to the voltagesource; and a second conductive path extending from the alarm connectionof the second socket not connected to the voltage source.
 44. The powerdistribution bus alarm circuit of claim 43, further comprising an alarmcircuit linked to the alarm connections of the first and second socketsthrough the first and second conductive paths, the alarm circuit beingresponsive to a voltage being applied across the alarm connections ofthe first or second sockets.
 45. The power distribution bus alarmcircuit of claim 43, further comprising: a first alarm circuit linked tothe alarm connection of the first socket through the first conductivepath, the first alarm circuit being responsive to a voltage beingapplied across the alarm connections of the first socket; and a secondalarm circuit linked to the alarm connections of the second socketthrough the second conductive path, the second alarm circuit beingresponsive to a voltage being applied across the alarm connections ofthe second socket.